Method for polymerization and copolymerization of alpha-olefin

ABSTRACT

The present invention relates to a method of polymerization or co-polymerization of olefin under the catalyst system which comprises (a) a solid complex titanium catalyst comprising of a magnesium compound, a titanium compound, and an internal electron donor; (b) an organometallic compound of metal of Group I or Group III on the Periodic Table; and (c) two of external electron donors comprising an external electron donor (1) and an external electron donor (2), wherein the ratio of the MFR (1) to the MFR (2) is 2˜10, the MFR (1) being that of the homopolymer (1) obtained by using said external electron donor (1) with said solid complex titanium catalyst (a) and the organometallic compound (b), and the MFR (2) being that of the homopolymer (2) obtained by using said external electron donor (2) under the identical polymerization reaction conditions of said external electron donor (1), and wherein the NMR pentads of the homopolymer (1) and the homopolymer (2), respectively, are 95.5% or more.

BACKGROUND OF INVENTION

The present invention relates to a method of producing olefin polymersor copolymers of high stereospecificity at a high rate of yields with abroad molecular weight distribution.

In general, polypropylene has characteristics of enhanced strength andheat-resistance at a broader molecular weight distribution and higherstereospecificity. As such, many attempts were made to broaden themolecular weight distribution and improve stereospecificity. Recently,Mitsui Petrochemical Industries, Ltd. and other well-known Europeancompanies have developed a polymerization method, by means of usingspecific silicon compounds, for polymers of high yields andstereospecificity (e.g., Korean Pat. Pub. No. 92-2488, U.S. Pat. No.4,990,479, EP Laid-Open No. 350,170A, Chinese Pat. No. 1,040,379), ascompared to those of the conventional methods. However, it was verydifficult to produce polymers of the broad molecular weight and high MFR(Melt Flow Rate) due to the low hydrogen response. Further, in order tobroaden the molecular weight distribution of the polymers, it was commonto use a method of producing and then mixing olefin polymers ofdifferent molecular weight distributions from one another in a number ofpolymerization reactors. Yet, this method takes too much time and hasdisadvantages in that the products thereof are non-homogeneous.

In a recent report, from Mitsui Petrochemical of Japan(publication No.93-665, of Korea Patent), a method has been proposed in which an olefinpolymer with a wider distribution of molecular weights is produced bythe use of two particular electron donors, from which homopolyolefinshaving the ratio of the melt flow rate (MFR) if greater than 31.6 arerespectively polymerized in the same polymerization conditions. In thiscase, however, the catalyst's activity is reduced too low and thestereospecificity of polymer is too low for it to be commerciallyuseful.

Meanwhile, many other techniques are known to produce polymers orcopolymers of high stereospecificity by the use of solid complextitanium catalysts containing magnesium with electron donors, and alsotitanium and a halogen, as catalyst for polymerization orcopolymerization of α-olefin which contains more than three atoms ofcarbon (e.g. Japanese, Pts. Laid-Open Nos. S48-16986 and S48-16987, Ger.Pts. Laid-Open Nos. 2,153,520; 2,230,672; 2,230,728; 2,230,752; and2,553,104)

These references reveal the use of mixture components of particularcatalysts and the process for forming these catalysts. As is well known,the characteristics of these catalysts, containing solid complextitanium, vary from catalyst to catalyst, in accordance with thedifferent mixtures of components, different combinations of processesfor formation, and the different combinations of these conditions.Therefore, it is very difficult to predict what effects can be obtainedfrom a catalyst produced under a given set of conditions. Often, acatalyst having undesirable effect is produced. It is also often truethat such characteristics as the activity of the catalyst or thestereospecificity of the polymer do not turn out to be adequate even ifthe catalyst is made under proper conditions, if proper externalelectron donors are not used.

The solid complex titanium catalyst containing magnesium, titanium, andhalogen is no exception. In polymerizing or copolymerizing α-olefincontaining more than three atoms of carbon, in the presence of hydrogenand with the use of a catalyst composed of titanium and anorganometallic compound of metals belonging to Groups I through IV onthe periodic table of elements, if a co-catalyst composed of titaniumtrichloride obtained by reducing titanium tetrachloride using metallicaluminum, hydrogen, or an organic aluminum compound is used, along withsuch electron donors as are known to restrain the formation of amorphouscopolymer, the effects vary depending upon the electron donors used. Thecause is accepted to be that the electron donors are not mere inertadditives, rather, they combine with the magnesium and titaniumcompounds electronically and sterically, thereby fundamentally alteringthe structure of the solid complex catalyst.

SUMMARY OF INVENTION

In an embodiment, a method of producing olefin polymers and co-polymersof broad molecular weight distribution, to the extent of a high MFR,while maintaining high stereospecificity and activity of a catalyst isdescribed.

In another embodiment, the present invention provides a method forproducing a polypropylene and propylene copolymer adequate for use inproduction of film easily capable of being heat-sealed, transparent, andanti-blocking property, also adequate for impact resistance, fluidityand low temperature heat-sealable is described.

DETAILED DESCRIPTION OF INVENTION

The present invention provides a method for polymerizing orcopolymerizing an α-olefin using the catalyst system comprising:

(a) a solid complex titanium catalyst containing magnesium, ahalogen-containing titanium compound, and, as internal electron donor,an ester polycarboxylate;

(b) an organometallic compound of a metal of Group I and III on theperiodic table of elements;

(c) two of external electron donors comprising an external electrondonor (1) and an external electron donor (2), wherein the ratio of theMFR (1) to the MFR (2) is 2˜10, the MFR (1) being that of thehomopolymer (1) obtained by using said external electron donor (1) withsaid solid complex titanium catalyst (a) and the organometallic compound(b), and the MFR (2) being that of the homopolymer (2) obtained by usingsaid external electron donor (2) under the identical polymerizationreaction conditions of said external electron donor (1), and wherein theNMR pentads of the homopolymer (1) and the homopolymer (2),respectively, are 95.5% or more.

The solid complex titanium catalyst (a) used for polymerization orcopolymerization of an α-olefin includes magnesium, a halogen-containingtitanium compound, and, as internal electron donor, esterpolycarboxylate. The solid complex titanium catalyst used in the presentinvention has an excellent level of catalytic activity, compared withexisting titanium catalysts, and is capable of creating a polymer havinga broad molecular weight distribution and a high stereospecificity. Ithas a halogen/titanium molar ratio more than about 4; it is also a solidcomplex with practically no titanium compound separating out when washedin hexane at room temperature. The chemical construction of this solidcomplex is not known but it is presumed that the atoms of magnesium, aswell as those of titanium, are firmly linked by halogen. In anembodiment of the solid complex titanium used in the present invention,the halogen/titanium molar ratio is more than about 5, preferably morethan about 8; a magnesium/titanium molar ratio over about 3, furtherpreferably from about 5 to about 50, the electron donor/titanium molarratio about 0.2 to about 6, preferably about 0.4 to about 3, even morepreferably about 0.8 to about 2. The specific surface area is more than10 m²/g, preferably more than about 50 m²/g, more preferably more thanabout 100 m²/g. The X-ray spectrum of the solid complex titaniumcatalyst preferably shows either amorphous characteristics in disregardof the starting magnesium, or characteristics more amorphous thanordinary magnesium dihalide on the market.

The solid complex titanium catalyst may be produced by many methods. Asthe most widely practiced method, contacting a non-reductive magnesiumcompound with a titanium compound which contains halogen(s), andtreating the product thereof, if necessary, with an electron donor, andthese methods can all be used in the present invention also. Some ofthese methods are revealed in Ger. Pts. Laid-Open Nos. 2,230,672;2,504,036; 2,553,104; and 2,605,922; and Japanese Pat. Laid-Open Nos.S51-28189; S51-136625; and 52-87486. The conventional method forproducing the solid complex titanium compound, beginning from a liquidmagnesium solution and containing an electron donor in the form of aliquid titanium compound, is described in Japanese pat. Laid-Open No.S54-40293.

The non-reductive magnesium compounds may include such magnesium halidesas magnesium chloride, magnesium bromide, magnesium iodide, andmagnesium fluoride; such alkoxymagnesium halides as methoxy magnesiumchloride, ethoxymagnesium chloride, isopropoxymagnesium chloride,butoxymagnesium chloride, octoxymagnesium chloride; sucharyloxymagnesium halides as phenoxymagnesium chloride, andmethylphenoxymagnesium chloride; such alkoxymagnesiums asethoxymagnesium, isopropoxymagnesium, butoxymagnesium andoctoxymagnesium; such aryloxymagnesium as phenoxymagnesium anddimethylpenoxymagnesium; and such magnesium salts of acid aslaurylmagnesium and magnesium stearate. Magnesium compounds may be usedin complex compounds whit other metals or with mixtures of other metals.A mixture of two or more magnesium compounds may also be used.Preferable magnesium compounds are halogen-containing magnesiumcompounds, and more preferable are magnesium chloride, alkoxymagnesiumchloride, most preferably alkoxymagnesium chloride and aryloxymagnesiumchloride which have C1 to C14 alkoxy group, yet preferablyaryloxymagnesium chloride which has C6 to C20 aryloxy group.

The magnesium compounds listed above can be generally represented bybrief general expressions, but there arise occasions at times whereother closely related magnesium compounds cannot be, because ofdifferent production methods. In such case, they are generally believedto be mixtures of these compounds. For instance, those compoundsobtained by reacting magnesium metals with alcohol or phenol in thepresence of halosilane, phosphorus pentachloride, or thionyl chloride,or by heat-dissolution of Grignard reagent, or by dissolving Grignardreagent using hydroxyl groups, carbonyl ester groups, ether groups orothers are all considered mixtures of a variety of compounds accordantwith the different reagents or the different degrees of reaction; suchcompounds are also usable in the present invention.

In an embodiment, non-reductive liquid magnesium compounds or solutionsof magnesium compounds in hydrocarbon solvents are mainly used. Suchcompounds in the liquid state can be produced by reacting thenon-reductive magnesium compounds listed above with at lest one or moreelectron donors chosen from a group that includes alcohol, organiccarboxylic acid, aldehyde, amines, and their mixtures in the presence orabsence of a hydrocarbon solvent which can dissolve those magnesiumcompounds given above.

The hydrocarbon solvents used for the purpose include, for example,aliphatic hydrocarbons such as pentane, hexane, heptane, octane, decane,dodecane, and kerosene; alicyclic hydrocarbons such as cyclopentane,methylcyclopentane, cyclohexane, and methylcyclohexane; such aromatichydrocarbons as benzene, toluene, xylene, ethylbenzene, cumen, andcymen; and halogenated hydrocarbons such as dichloroethane,dichloropropane, dichloroethylene, trichloroethylene, carbontetrachloride, and chlorobenzene.

The magnesium compound solution of hydrocarbon solvents, can be producedby simple mixture, or by heating during mixing, or by mixing in thepresence of an electron donor selected from the group that includesalcohol, aldehyde, amine, carboxylic acid, or their mixtures, or even bymixing these mixtures with other electron donors and heating them.However, this production method can be altered depending upon the typeof magnesium and the solutions. When dissolving hydrogen-containingmagnesium compound in a hydrocarbon solution, using alcohol as theelectron donor, the quantities and proportions of the alcohol may differdepending upon the quantity and kinds of magnesium compounds and thehydrocarbon solvent, but it is desirable to use at least 0.5 mol of analcohol per 1 mol of the magnesium compound, preferably 1.0 to 20 mols,more preferably about 2.0 mols to about 10 mols.

In the case where alcohol having at least 6 atoms of carbon is used, ifat least 0.5 mol, or preferably at least 1.0 mol of alcohol, per 1 molof the halogen-containing magnesium compound, the halogen-containingcompound can be dissolved and a catalyst component with high activitycan be obtained with the use of only a small quantity of alcohol. Ifalcohol with 5 or fewer carbon atoms is used, the total quantity of thealcohol should be at least about 15 mols to 1 mol of the magnesiumcompound, and the catalyst component thus produced will have loweractivity than when alcohol is used in the way stated above. Meanwhile,if aromatic hydrocarbon is used as the hydrocarbon solvent, thehydrogen-containing magnesium compound can be dissolved, regardless ofthe type of alcohol, by about 20 mols, preferably about 1.5 mols to 12mols of alcohol, per 1 mol of the magnesium compound.

The reaction of halogen-containing magnesium and alcohol is performedpreferably in a hydrocarbon solvent. This reaction is performed,dependent upon the kinds of the magnesium compound and alcohol, at roomtemperature or higher, e.g. in the range from about 30 degrees C. to 200degrees C., or more preferably about 60 degrees C. to 150 degrees C.,for a time in the range from about 15 minutes to about 5 hours, morepreferably about 30 minutes to about 3 hours.

The alcohols used as electron donors in formation of a liquid magnesiumcompound include such aliphatic alcohols as 2-methylpentanol,2-ethylpentanol, 2-ethylbutanol, n-heptanol, n-octanol, 2-thylhexanol,decanol, dodecanol, tetradecyl alcohol, undecanol, oleyl alcohol, andstearyl alcohol; such alicyclic alcohols as cyclohexanol andmethylcyclohexanol; and such aromatic alcohols as benzyl alcohol,methylbenzyl alcohol, isopropylenebenzylalcohol, a-methylbenzyl alcohol,and a,a-dimethylbenzyl alcohol, which all have at least 6 or, preferably6 to 20 carbon atoms. For alcohols with 5 or fewer carbon atoms,methanol, ethanol, propanol, butanol, ethyleneglycol and methylcarbitoland the like can be used.

The magnesium compounds in liquid form, produced as above, arecrystallized into globular solids once again with the use of silicontetrahalide, silicon alkylhalide, tin tetrahalide, tin alkylhalide, tinhydrohalide, titanium tetrahalide, and the like. The quantity of siliconcompounds, tin compounds, or titanium compounds for use in therecrystallizing of liquid magnesium compounds into globular solids maybe varied form case to case. It can be 0.1 mol to 20 mols per 1 mol ofthe magnesium compound. Preferably, it is 0.1 mol to 10 mols, morepreferably 0.2 mol to 2 mols. The shapes and magnitudes of the magnesiumcarriers will also vary accordant with the conditions of the reaction.At the time of mixing the two compounds they must be maintained at aproperly low temperature in order for them not to solidify during thereaction, with the product then being slowly heated to yield a solid.The temperature for recrystallizing of a liquid magnesium compoundranges from about −70 degrees C. to about 200 degrees C. In general, toobtain granular or globular forms high temperature is, preferably,avoided during the process of mixing. However, if the temperature ofreaction is too low, precipitation of solid products will not takeplace, and, therefore, this reaction should be performed, preferably, atabout 20 degrees C. to 150 degrees C.

The magnesium compound thus obtained may be reacted with a liquidtitanium compound, in the presence of an internal electron donor,whereby a solid complex titanium catalyst is obtained. The titaniumcompound in liquid form to be reacted with a magnesium compound ispreferably the tetravalence titanium compound in the general expression:

Ti(OR)_(m)X_(4−m)(wherein R is a hydrocarbon group, X halogen atoms, mis a number from 0 to 4). The R represents an alkyl group with from 1through 10 carbon atoms. Various titanium compounds can be used,titanium tetrahalides such as TiCl₄, TiBr₄, and Til₄, alkoxytitaniumtrihalides such as Ti(OCH₃)Cl₃, Ti(OC₂H₅)Cl₃, Ti(OC₄H₉)Cl₃,Ti(OC₂H₅)Br₃, and Ti(O(i-C₂H₅))Br₃; alkoxytitanium dihalides such asTi(OCH₃)₂Cl₂, Ti(OC₂H₅)₂Cl₂, Ti(OC₄H₉)₂Cl₂, and Ti(OC₂H₅)₂Br₂;alkoxytitanium halides such as Ti(OCH₃)₃Cl, Ti(OC₂H₅)₃Cl, Ti(OC₄H₉)₃Cl,and Ti(OC₂H₅)₃Br; and tetraalkoxytitanium mixtures such as Ti(OCH₃)₄,Ti(OC₂H₅)₄, and Ti(OC₄H₉)₄.

The titanium compound is used in a proportion of at least 1 mol,preferably 3mols to about 200 mols, or, more preferably, approximately 5mols to 100 mols, per 1 mol of the non-reductive magnesium compound. Itis preferable to mix the magnesium compound with the liquid titaniumcompound at a low temperature, slowly raising it. For instance, the twocompounds are brought into contact at −70 degrees C. to about 50 degreesC. at first to avoid a quick reaction, and the temperature is slowlyraised to a temperature in the range from about 50 degrees C. to 150degrees C. for the reaction to take effect for sufficient time, afterwhich the product is washed in the hydrocarbon used for thepolymerization reaction until no isolated titanium is detected. By thismethod an excellent solid complex titanium catalyst can be produced.

The internal electron donors used in production of the solid complextitanium catalyst can be generally, oxygen-containing electron donorssuch as water, alcohols, phenols, aldehydes, carboxylic acids, esters,ethers, and acid amides; along with nitrogen-containing electron donorssuch as ammonia, amines, nitrites, and isocyanate; and particularlyalcohols having from 1 to 18 carbon atoms such as methanol, ethanol,propanol, pentanol, hexanol, octanol, dodecanol, octadecylalcohol,benzylalcohol, phenylethylalcohol, cumylalcohol, andisopropylbenzylalcohol; ketones which have from 6 to 15 carbon atoms andwhich can contain lower alkyl groups such as phenol, cresol, xylene,ethylphenol, propylphenol, cumylphenol, and naphthol; aldehydes whichhave from 2 to 15 carbon atoms such as acetaldehyde, propionaldehyde,octylaldehyde, benzaldehyde, tolualdehyde, and naphthalaldehyde; organicacid esters having from 2 to 18 carbon atoms such as methyl formate,methyl acetate, ethyl acetate, vinyl acetate, propyl acetate, octylacetate, cyclohexyl acetate, ethyl propionate, methyl butyrate, ethylvalerate, chloromethyl acetate, dichloroethyl acetate, methylmethacrylate, ethyl crotonate, ethyl cyclohexyl carboxylate, phenylbenzoate, benzyl benzoate, methyl toluate, ethyl toluate, amyl toluate,ethyl ethyl benzoate, methyl anisate, ethyl anisate, ethylethoxybenzoate, g-butyrolactone, s-valerolactone, cumalin, phthalide,cyclohexyl acetate, ethyl propionate, methyl butyrate, methyl valerate,methyl chloroacetate, ethyl dichloroacetate, methyl methacrylate, ethylcycloate, phenyl benzoate, ethyl toluate, ethyl toluate, propylbenzoate, butyl benzoate, cyclohexyl benzoate, amyl toluate, methylenecarbonate, and ethylene carbonate; halogen compounds having from 2 to 15carbon atoms such as acetyl chloride, benzyl chloride, chlorotoluate,and chloroanisate; ethers such as methyl ether, ethyl ether, ispropylether, butyl ether, amyl ether, tetrahydrofuran, anisole and diphenylether; amines such as methyl amine, ethyl amine, diethyl amine, tributylamine, piperidine, tribenzyl amine, aniline, pyridine, pyroline, andtetramethylene diamine; nitriles such as acetonitrile, benzonitrile, andtolunitrile; and compounds of aluminum, silicon, tin, and the like whichhave the above-said functional groups in their molecules; in addition tothese, catalysts reacted with certain electron donors are used in thepresent invention to produce an α-olefin polymer with improvedstereospecificity and greater yield than otherwise. The preferableinternal electron donors used in the present invention to produce asolid complex titanium catalyst are, in particular, ester derivatives ofmonoethylene glycol(MEG), diethylene glycol(DEG), triethyleneglycol(TEG), polyethylene glycol(PEG), monopropylene glycol(MPG), anddipropylene glycol(DPG) such as, acetate, propionate, n- andiso-butyrate, benzoate, toluate, etc., the benzoates are monoethyleneglycol monobenzoate, monoethylene glycol dibenzoate, diethylene glycolmonobenzoate, diethylene glycol dibenzoate, diethylene glycolmonobenzoate, triethylene glycol dibenzoate, monopropyl glycolmonobenzoate, dipropylene glycol monobenzoate, tripropylene glycolmonobenzoate, and others. These electron donors can be used in a mixtureof two or more kinds, and particularly, esters of the aromatic group arepreferable. These electron donors are not always needed at the start,they may also be introduced during the production of the solid complextitanium catalyst, and they may also be used as additives to othercompounds or in the form of a complex. The quantity of the internalelectron donor can be changed as required. It may be about 0.01 mol toabout 10 mols, preferably about 0.01 mol to 5 mols, or furtherpreferably 0.05 mol to about 1 mol, per 1 mol of the magnesium compound.

The polymers obtained through a slurry polymerization by using theresultant solid catalyst are granular or globular with excellentstereospecificity, a high bulk density, and good fluidity.

The aforesaid solid complex titanium catalyst can be profitably used inpolymerization of such olefins as ethylene, propylene, and 1-butene or4-methyl-1-pentene. This catalyst can be especially profitably used inthe polymerization of α-olefin which has three or more carbon atoms,copolymerization of these, copolymerization of α-olefins which haveethylene by less than 10 mols, and in copolymerization of α-olefinswhich have both conjugated and nonconjugated dienes.

The organometallic compounds (b) used in the method of the presentinvention include, in particular, trialkyl aluminums such as triethylaluminum and tributyl aluminum; alkenyl aluminum such as triisoprenylaluminum; partly alkoxyfied alkyl aluminums, for example,dialkylaluminum alkoxides such as diethylaluminum ethoxide anddibutylaluminum butoxide; alkylaluminum sesquibalides and ethylaluminumdichlorides such as ethylaluminum sesquiethoxide and butylaluminumsesquiethoxide; alkylaluminum dihalide such as propylaluminum dichlorideand butylaluminum dibromide; partly halogenized aluminum, for example,dialkylaluminum hydrides and ethylaluminum ethoxychlorides such asdiethylaluminum hydrides and dibutylaluminum hydride; and partlyalkoxyfied and halogenized alkyl aluminums such as butylaluminumbutoxychloride and ethylaluminum ethoxybromide.

In addition to said solid complex titanium catalyst (a) and theorganometallic compound (b), the present invention uses, as an externalelectron donor component (c), under the equivalent reaction conditionsof polymerization, a mixture of an external electron donor (1) whichpolymerizes to high stereospecificity the polymers of relatively highmolecular weight, and an external electron donor (2) which polymerizesto high stereospecificity the polymers of relatively low molecularweight. Consequently, the present invention can produce polymers of highstereospecificity with a broad molecular weight distribution. The mixratio of the external electron donor (1) to the external electron donor(2), constituting the external electron donor component (c), is0.05:0.95 to 0.95:0.05 in terms of molar ratio, preferably 0.1:0.9 to0.9:0.1, or more preferably 0.3:0.7 to 0.7:0.3.

As for the external electron donor (1) used in the present invention, itis per 1 mol of the titanium atoms in the solid complex titaniumcatalyst (a) is from about 1 mol to 2,000 mols, preferably about 5 molsto about 500 mols. The ratio of component (c) of external electrondonors being from about 0.001 mol to 10 mols, or preferably about 0.01mol to about 2 mol, more preferably about 0.05 mol to about 1 mol per 1mol of the aluminum atoms of the components (b), as measured in terms ofthe silicon atoms.

The polymerization reaction using the catalyst of the invention isperformed in the same way as in the ordinary method where a Ziegler-typecatalyst is used. Note that this reaction is performed in the absence ofoxygen and water. The olefin polymerization reaction is performed,preferably, at a temperature in the range from about 20 degrees C. to200 degrees C., more preferably at about 50 degrees C. to 180 degreesC., and under a pressure ranging from about normal atmospheric pressureto 100 atmospheres, preferably from about 2 atmospheres to 50atmospheres. The reaction can be performed either by batches, orsemi-batch, or continuously, and can also be performed in two or moresteps with different reaction conditions.

Below, embodiment of the present invention will be shown in furtherdetail through examples and comparative examples:

EXAMPLE 1

[Production of Solid Titanium Catalyst, Components (a)]

Into a 1-liter glass reactor 5g (0.053 mol) of MgCl₂ and 50 mol ofn-decane were put and stirred in a nitrogenous atmosphere for an hour,then 25 ml (0.16 mol) of 2-ethyl-1-hexanol was slowly added to themixture. The solution was heated up to 120 degrees C. and left to reactfor two hours, then 2 ml of diisobutylphthalate was added to it forreaction for an hour to obtain a homogeneous solution. The temperaturewas lowered to room temperature, 30 ml of TiCl₄ was added by drops, thereaction temperature was raised to 90 degrees C., and the solution wasleft to react for two hours to form a solid carrier. 2.0g (0.007 mol) ofmonoethyleneglycol dibenzoate was added as the second electron donor,and the solution left to react at 90 degrees C. for an hour. The solidmatter was recovered, and washed in refined hexane until no isolatedtitanium tetrachloride could be found in the washing liquid. Refinedheptane was put to the carrier obtained, 40 mol of TiCl₄ was droppedinto it for an hour, it was heated to 100 degrees C., and left to reactfor two hours. The solid catalyst thus produced was washed in refinedhexane until no isolated titanium components were detected in thehexane, then dried, and stored away in a nitrogenous atmosphere forlater use. The solid complex titanium catalyst (a) contained preferableto use an organic silicone compound of the alkyldimethoxysilane typecontaining a cyclopentyl group, a cyclopentenyl group, acyclopentadienyl group, or two alkyl groups selected from the derivativegroups thereof. More specifically, an organometallic compound of analkyldimethoxysilane type is used, e.g., dicyclopentylmethoxysilane,bis(2,5-dimethylcyclopentyl)dimethoxysilane,dicyclopentenyldimethoxysilane, di(3-cyclopentenyl)dimethoxysilane,bis(2,5-dimethyl-3-cyclopentenyl)dimethoxysilane,di-2,4-cyclopentadienyldimethoxysilane,bis(2,5-dimethyl-2,4-cyclopentadienyl)dimethoxysilane,bis(1-methyl-1-cyclopentylethyl)dimethoxysilane,cyclopentylcyclopentenyldimethoxysilane,cyclopentylcyclopentadienylmethoxysilane, etc.

In addition, as for the external electron donor (2), an organic siliconecompound is used, which is of an alkyldimethoxysilane type containing acyclopentyl group, a cyclopentenyl group, a cyclopentadienyl group, orone or less of an alkyl group selected from the derivative groupsthereof. More specifically, it is preferable to use an organometalliccompound of an alkylmethoxysilane type, e.g.,diisopropyldimethoxysilane, di-secondary-butyldimethoxysilane,dicyclohexyldimethoxysilane, isobutylisopropyldimethoxysilane,isobutyl-secondary-butyldimethoxysilane,isobutylcyclopentyldimethoxysilane,isopropyl-secondary-butyldimethoxysilane,isopropylcyclopentyldimethoxysilane, isopropylcyclohexyldimethoxysilane,isobutylcyclohexyldimethoxysilane,secondary-butylcyclopentyldimethoxysilane,secondary-butylcyclohexylsilane, etc.

The polymerization reaction can be performed in a liquid or gaseousphase, but as the polymer produced with the use of the catalysts of thepresent invention is of even granularity and its bulk density is high,it is more fit to gaseous phase polymerization.

In polymerization of a liquid, such inactive solvents as hexane,heptane, and kerosene can be used as the reaction medium, olefin itselfmay also serve as the reaction medium. The preferable degree ofconcentration of the solid complex titanium catalyst (a), in the case ofliquid polymerization is from about 0.001 mmol to about 5 mmols per 1liter of the total of all reactants and solvents, as measured in termsof the titanium atoms, or more preferably about 0.001 mmol to about 0.5mmols. In the case of gaseous polymerization, it is, also in terms ofthe titanium atoms, from about 0.001 mmol to about 5 mmols, morepreferably about 0.001 mmol to about 1.0 mmol, yet more preferably 0.01mmol to about 0.5 mmols per 1 liter of the total of all reactants andsolvents.

The ratio of the aluminum atoms of component (b) of the organometalliccompound titanium atoms by 2.5wt %.

(Polymerization)

A high pressure reactor of 2-liter capacity was washed with propylene,38 mg of catalyst (titanium components being 0.02 mmol, measured interms of the titanium atoms) in a glass vial was placed inside thereactor, and the reactor was evacuated and refilled with nitrogen threetimes. Then 10 mmol of triethylaluminum was put into the reactortogether with 0.5 mmol of dicyclopentyldimethoxysilane, 0.5 mmol ofdiisopropyldimethoxysilane, and 1000 ml of n-hexane, these latter asexternal electron donors. After the hexane was put in, 100 Nml (0degrees C, 1 atm) of hydrogen was put in, and the temperature was raisedto 70 degrees C. Propylene gas, its water and oxygen previously removedin an oxygen scavenger and molecular sieve trap, was put in apolymerization reactor (2-liter Parr reactor, Model 4521) through an MFC(Mass Flow Controller). When the propylene reached gas/liquidequilibrium at an overall pressure of 7 kg/cm², the vial inside thereactor was broken with the stirrer, thus letting the reaction begin.The reaction was left to continue for one hour, then the high pressurecontents were cooled to room temperature, and 10 ml of ethanol was addedthereto to end the catalyst activity. The polymer thus produced wasrecovered, dried in a vacuum oven at 50 degrees C. for about six hours,and thereby 136.8 g of polypropylene was obtained in powder from. Inthis polymer, the rate of residue remaining after extraction by boilingin n-heptane was 99.4%, while the bulk density was 0.39 g/ml, NMR pentadportion was 96.4%, the MFR 2.4 and the molecular weight distribution(Mw/Mn) 7.5. The melt flow rate was measured by ASTM D1238 at 230 ° C.with a load of 2.16 Kg.

EXAMPLE 2

Except for the amount of hydrogen of 300N ml at the time ofpolymerization, the polymerization was carried out under the identicalconditions of Example 1, and the results thereof are shown in Table 1.

EXAMPLE 3

Except for the amount of hydrogen of 500N ml at the time ofpolymerization, the polymerization was carried out under the identicalconditions of Example 1, and the results thereof are shown in Table 1.

EXAMPLE 4

0.7 mmol of dicyclopentyldimethoxysilane and 0.3 mmol ofdiisopropyldimethoxysilane as the external electron donors were used forpolymerization by means of the catalyst produced in Example 1, and theresults thereof are shown in Table 1.

EXAMPLE 5

0.6 mmol of dicyclopentyldimethoxysilane and 0.4 mmol ofdiisopropyldimethoxysilane as the external electron donors were used forpolymerization by means of the catalyst produced in Example 1, and theresults thereof are shown in Table 1.

EXAMPLE 6

0.4 mmol of dicyclopentyldimethoxysilane and 0.6 mmol ofdiisopropyldimethoxysilane as the external electron donors were used forpolymerization by means of the catalyst produced in Example 1, and theresults thereof are shown in Table 1.

EXAMPLE 7

0.3 mmol of dicyclopentyldimethoxysilane and 0.7 mmol ofdiisopropyldimethoxysilane as the external electron donors were used forpolymerization by means of the catalyst produced in Example 1, and theresults thereof are shown in Table 1.

Comparative Example 1

1.0 mmol of dicyclopentyldimethoxysilane as the external electron donorwas used for polymerization by means of the catalyst produced in Example1, and the results thereof are shown in Table 1.

Comparative Example 2

1.0 mmol of diisopropyldimethoxysilane as the external electron donorwas used for polymerization by means of the catalyst produced in Example1, and the results thereof are shown in Table 1.

Comparative Example 3

1.0 mmol of vinyltriethoxysilane as the external electron donor was usedfor polymerization by means of the catalyst produced in Example 1, andthe results thereof are shown in Table 1.

Comparative Example 4

0.5 mmol of dicyclopentyldimethoxysilane and 0.5 mmol ofvinyltriethoxysilane as the external electron donors were used forpolymerization by means of the catalyst produced in Example 1, and theresults thereof are shown in Table 1.

Comparative Example 5

Except for the amount of hydrogen of 300N ml at the time ofpolymerization, the polymerization was carried out under the identicalconditions of

Comparative Example 4, and the results thereof are shown in Table 1.Comparative Example 6

Except for the amount of hydrogen of 500N ml at the time ofpolymerization, the polymerization was carried out under the identicalconditions of Comparative Example 4, and the results thereof are shownin Table 1.

Comparative Example 7

0.4 mmol of dicyclopentyldimethoxysilane and 0.6 mmol ofvinyltriethoxysilane as the external electron donors were used forpolymerization by means of the catalyst produced in Example 1, and theresults thereof are shown in Table 1 .

Comparative Example 8

0.6 mmol of dicyclopentyldimethoxysilane and 0.4 mmol ofvinyltriethoxysilane as the external electron donor were used forpolymerization by means of the catalyst produced in Example 1, and theresults thereof are shown in Table 1.

Comparative Example 9

1.0 mmol of dimethyldiethoxysilane as the external electron donor wasused for polymerization by means of the catalyst produced in Example 1,and the results thereof are shown in Table 1.

Comparative Example 10

0.6 mmol of dicyclopentyldimethoxysilane and 0.4 mmol ofdimethylethoxysilane as the external electron donors were used forpolymerization by means of the catalyst produced in Example 1, and theresults thereof are shown in Table 1.

Comparative Example 11

Except for the amount of hydrogen of 300N ml at the time ofpolymerization, the polymerization was carried out under the identicalconditions of Comparative Example 10, and the results thereof are shownin Table 1.

Comparative Example 12

Except for the amount of hydrogen of 500N ml at the time ofpolymerization, the polymerization was carried out under the identicalconditions of Comparative Example 10, and the results thereof are shownin Table 1.

TABLE 1 Result of Polymerization Polymerization Condition ResultExternal electron External electron Activity Melt flow Residue afterdonor (1) donor (2) H₂ (kg-PP/g- rate (g/10 min.) extraction with NMRBulk Exmp Kind mmol Kind mmol (Nml) cat.h.) (230° C., 2.16 Kg) n-heptane(%) pentad (%) Density (g/ml) Mw/Mn Exmp 1 DCPDMS 0.5 DIPDMS 0.5 100 3.62.4 99.4 96.4 0.39 7.5 Exmp 2 DCPDMS 0.5 DIPDMS 0.5 300 4.3 8.0 99.296.3 0.39 7.2 Exmp 3 DCPDMS 0.5 DIPDMS 0.5 500 4.2 17.7 98.9 96.3 0.347.0 Exmp 4 DCPDMS 0.7 DIPDMS 0.3 100 4.2 2.0 99.4 96.3 0.29 6.2 Exmp 5DCPDMS 0.6 DIPDMS 0.4 100 4.3 3.3 99.5 96.2 0.36 6.0 Exmp 6 DCPDMS 0.4DIPDMS 0.6 100 3.4 2.9 99.2 96.3 0.40 6.9 Exmp 7 DCPDMS 0.3 DIPDMS 0.7100 3.8 3.1 99.0. 96.2 0.39 7.2 Comp 1 DCPDMS 1.0 — — 100 4.8 1.4 99.396.4 0.40 5.7 Comp 2 DTPDMS 1.0 — — 100 2.8 4.5 98.5 96.1 0.26 5.3 Comp3 VTES 1.0 — — 100 0.6 39 95.4 90.3 0.35 5.7 Comp 4 DCPDMS 0.5 VTES 0.5100 3.1 1.7 98.2 95.5 0.32 6.6 Comp 5 DCPDMS 0.5 VTES 0.5 300 3.6 6.697.5 95.4 0.32 6.1 Comp 6 DCPDMS 0.5 VTES 0.5 500 3.2 15.3 97.2 95.10.34 6.8 Comp 7 DCPDMS 0.4 VTES 0.6 100 3.3 1.4 98.4 95.6 0.36 5.8 Comp8 DCPDMS 0.6 VTES 0.4 100 2.9 2.1 97.8 94.8 0.36 6.0 Comp 9 DMDES 1.0 —— 100 0.5 40 94.8 89.8 0.36 5.8 Comp 10 DCPDMS 0.6 DMDES 0.4 100 3.0 1.698.3 95.3 0.31 6.6 Comp 11 DCPDMS 0.6 DMDES 0.4 300 3.5 6.7 97.2 95.60.38 5.4 Comp 12 DCPDMS 0.6 DMDES 0.4 500 3.2 14.6 97.3 95.3 0.27 4.5*DCPDMS: Dicylopentyldimethoxysilane  *VTES: Vinyltriethoxysilane*DIPDMS: Diisopropyldimethoxysilane   *DMDES: Dimethyldiethoxysilane

As explained above, according to the method of the present invention, itis possible to obtain olefin polymers of a broad molecular weightdistribution and high apparent density while maintaining polymers'highstereospecificity and activity.

Further modifications and alternative embodiments of various aspects ofthe invention will be apparent to those skilled in the art in view ofthis description. Accordingly, this description is to be construed asillustrative only and is for the purpose of teaching those skilled inthe art the general manner of carrying out the invention. It is to beunderstood that the forms of the invention shown and described hereinare to be taken as the presently preferred embodiments. Elements andmaterials may be substituted for those illustrated and described herein,parts and processes may be reversed, and certain features of theinvention may be utilized independently, all as would be apparent to oneskilled in the art after having the benefit of this description of theinvention. Changes may be made in the elements described herein withoutdeparting from the spirit and scope of the invention as described in thefollowing claims.

What is claimed is:
 1. A method for polymerization or copolymerizationof α-olefin, using a catalytic system comprising: (a) a solid complextitanium catalyst comprising magnesium, a halogen-containing titaniumcompound, and at least one internal electron donor; (b) anorganometallic compound of metal belonging to the group consisting ofGroups I and III on the periodic table of elements; and (c)dicyclopentyldimethoxysilane and diisopropyldimethoxysilane as externalelectron donors.
 2. The method for polymerization or copolymerization ofα-olefin according to claim 1, in which said internal electron donor ischosen from the group of esters of monoethyleneglycol, diethyleneglycol,triethylenglycol, polyethyleneglycol, monopropyleneglycol anddipropyleneglycol.
 3. The method for polymerization or copolymerizationof α-olefin according to claim 1, in which the organometallic compoundis trialkylaluminum.